[PHP知识库]解决laravel数据表迁移SQLSTATE[42000]问题

• 报错信息如下：

	 SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 1000 bytes (SQL: alter table `roles` add unique `roles_name_guard_name_unique`(`name`, `guard_name`))

  at F:\php\laravel-admin-cms-master\vendor\laravel\framework\src\Illuminate\Database\Connection.php:692
    688▕         // If an exception occurs when attempting to run a query, we'll format the error
    689▕         // message to include the bindings with SQL, which will make this exception a
    690▕         // lot more helpful to the developer instead of just the database's errors.
    691▕         catch (Exception $e) {
  ? 692▕             throw new QueryException(
    693▕                 $query, $this->prepareBindings($bindings), $e
    694▕             );
    695▕         }
    696▕

  1   F:\php\laravel-admin-cms-master\vendor\laravel\framework\src\Illuminate\Database\Connection.php:485
      PDOException::("SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 1000 bytes")

  2   F:\php\laravel-admin-cms-master\vendor\laravel\framework\src\Illuminate\Database\Connection.php:485
      PDOStatement::execute()

• 最有效解决办法
  • 根据对应报错字段信息，直接设置该字段key长度即可，不需要添加Schema::defaultStringLength(191);如下图

   Schema::create($tableNames['roles'], function (Blueprint $table) {
         $table->bigIncrements('id');
         $table->string('name');
         $table->string('title')->default ('');
         $table->string('guard_name',50);
         $table->timestamps();
  
         $table->unique(['name', 'guard_name']);
     });